I'm thinking something like this:
2x Bard ( Buff's )
1x Cleric ( Healing )
1x Warlock ( Debuffing / attacking )
1x Warrior ( Tanking )
3x Wizzard ( Attackers )
The 2 Bard don't need to have any sub class, their pretty much just there for the bufs, you can how ever let them attack if you want.. At higher level you can set them to keep using the MP recover skill, so have alot of spare inv. space on all the chars, just know that once both bards go to town at the same time, you'll have a big problem if you didnt bring MP
I dont think the Cleric really needs a sub class either, just let it heal/Reverse/buff Wizards and use bless.
With the Warlock, Warrior and Wizzards the best thing to do is to pick cler as sub, to reverse when needed and have Bless on you
All the time!.